scholarly journals Influence of soil properties on plant density and species richness of saline desert

2016 ◽  
pp. 81-90 ◽  
Author(s):  
Pradeep Kumar Pilania ◽  
Nilesh Sundarjibhai Panchal

El ambiente edáfico tiene una significativa influencia en la productividad. La salinidad es uno de los principales factores que afectan negativamente a la vegetación. Se estudió un ecosistema desértico de la India (Pequeño Rann de Kutch; 7020 ha) para medir la influencia de las propiedades del suelo en la vegetación. Tanto la riqueza de especies (SR) como la densidad de hierbas y arbustos/árboles (17.018 plantas m-2 y 8.617 plantas 10 m-2) fueron mayores en el punto 4, con valores altos de OC, OM, N, P, Ca y Fe (0.684, 1.179, 0.059 %, 42.338 kg ha-1, 170.732, 32.016 mg kg-1) y bajos niveles de arcilla, EC y Na (33.654%, 9.441dSm-1 y 68.699 mg kg-1). Valores altos de arcilla, Na y EC con bajo Ca y Fe resultaron en bajas densidades de SR (lugares 2 y 5). Las bajas SR y densidad se deben a bajas concentraciones de OC, OM, N, P, Fe, Ca y alta concentración de arcilla, Na y EC.Soil environment have significant influence on the productivity of land. Salinity is one of the major factors which negatively affect the vegetation. To measure the influence of soil properties on vegetation, desert ecosystem in India (Little Rann of Kutch of 7020 ha) was studied. Species richness (SR) as well as density for herbs and shrubs/tree (17.018 plants m-2 and 8.617 plants 10m-2) was highest in the site 4, with high OC, OM, N, P, Ca and Fe (0.684, 1.179, 0.059 %, 42.338 kg ha-1, 170.732 and 32.016 mg kg-1) and low clay, EC and Na (33.654%, 9.441dSm-1 and 68.699 mg kg-1). High amount of clay, Na and EC with low Ca and Fe results into low density with low SR (site 2 and 5). Low SR and density are due to low concentration of OC, OM, N, P, Fe, Ca and high concentration of clay, Na and EC.

Author(s):  
Shin Woong Kim ◽  
Matthias C. Rillig

AbstractWe collated and synthesized previous studies that reported the impacts of microplastics on soil parameters. The data were classified and integrated to screen for the proportion of significant effects, then we suggest several directions to alleviate the current data limitation in future experiments. We compiled 106 datasets capturing significant effects, which were analyzed in detail. We found that polyethylene and pellets (or powders) were the most frequently used microplastic composition and shape for soil experiments. The significant effects mainly occurred in broad size ranges (0.1–1 mm) at test concentrations of 0.1%–10% based on soil dry weight. Polyvinyl chloride and film induced significant effects at lower concentrations compared to other compositions and shapes, respectively. We adopted a species sensitivity distribution (SSD) and soil property effect distribution (SPED) method using available data from soil biota, and for soil properties and enzymes deemed relevant for microplastic management. The predicted-no-effect-concentration (PNEC)-like values needed to protect 95% of soil biota and soil properties was estimated to be between 520 and 655 mg kg−1. This study was the first to screen microplastic levels with a view toward protecting the soil system. Our results should be regularly updated (e.g., quarterly) with additional data as they become available.


2012 ◽  
Vol 463-464 ◽  
pp. 189-193
Author(s):  
Kong Zhai Li ◽  
Masaaki Haneda ◽  
Masakuni Ozawa

Maghemite (γ-FeSubscript text2OSubscript text3) and hematite (α-Fe2O3) nanoparticles with various dominant exposure crystal planes were prepared by several different methods. The structure and the reducibility of these materials were investigated by XRD, Raman and H2-TPR technologies, and their catalytic performance for propene oxidation was also discussed. The maghemite (γ-FeSubscript text2OSubscript text3) showed a better reducibility than hematite (α-FeSubscript text2OSubscript text3), but its activity for propene oxidation is relatively lower. The exposure crystal plane of hematite has a significant influence on its catalytic activity for propene oxidation. Among the prepared four samples, the hematite-1 sample showed the best activity. The selective growth of any planes with a relative low density of Fe atoms for the α-FeSubscript text2OSubscript text3 catalyst would lead to an obvious decrease in the catalytic activity.


2007 ◽  
Vol 26 (4) ◽  
pp. 229-244 ◽  
Author(s):  
Bibin John ◽  
C.P. Reghunadhan Nair ◽  
K.N. Ninan

Low-density phenolic syntactic foams with different volume percentages of microballoons were processed and their mechanical performance has been evaluated in terms of tensile, flexural, compressive and the corresponding specific properties. Tensile and flexural strength increased with volume fraction of microballoon and optimized at 72–74 percentage by volume of microballoon. Both the properties decreased with further addition of microballoon. The corresponding specific properties also manifested a similar order. Compressive and specific compressive strength decreased with increase in microballoon volume percentage. The flexural and compressive modulus values followed the same trend as the strength values. The properties of phenolic syntactic foams were compared with syntactic foams based on an addition cure phenolic resin, Propargyl Ether Novolac resin (PN). The mechanical properties of the latter were inferior to those of phenolic syntactic foams. The morphology of the failed samples as examined by SEM showed that failure occurred by a combination of matrix and microballoon failure at low microballoon loading whereas it occurred by microballoon cracking and resin to microballoon debonding at high concentration of filler. The dynamic mechanical analysis of phenolic and PN resin syntactic foams showed a higher use temperature for PN system in comparison to phenolic.


2003 ◽  
Vol 51 (1) ◽  
pp. 25-35 ◽  
Author(s):  
A. Y. Allam ◽  
G. R. El-Nagar ◽  
A. H. Galal

This investigation was carried out at the Experimental Farm of Assiut University during the summers of 2000 and 2001 to study the responses of two sunflower hybrids (Vidoc and Euroflora) to planting dates (May 1st, June 1st and July 1st) and planting densities (55,533, 83,300 and 166,600 plants/ha). The results indicated that the two varieties differed highly significantly in all studied traits except oil yield/ha. The highest seed yield (3.64 t/ha) was obtained with the variety Vidoc. In addition, the results revealed that the planting date exerted a highly significant influence on all vegetative growth traits along with yield and its components. Increasing plant density increased the seed and oil yield/ha. By contrast, the stem diameter, head diameter, 100-seed weight and seed yield/plant decreased with increasing plant density. The interaction between varieties and plant density had a highly significant effect on head diameter. The greatest head diameter (20.06 cm) was recorded for the variety Vidoc planted at lower density. Concerning the interaction between planting density and planting date, the highest seed yield (4.47 t/ha) was obtained from dense plants at the early sowing date, and the highest oil % (45.32) at the late planting date and the lowest plant density. The second order interaction exerted a highly significant influence on stem and head diameter in addition to seed yield/plant, where the highest value (78.13 g/plant) was obtained with the variety Vidoc planted on May 1st at the lowest plant density.


2002 ◽  
Vol 18 (5) ◽  
pp. 775-794 ◽  
Author(s):  
Luci Ferreira Ribeiro ◽  
Marcelo Tabarelli

Four structural types of cerrado vegetation were examined to test the following hypotheses: (1) there are predictable changes in woody plant density, species richness and life-history strategies from one structural type to another; and (2) plant species composition in the less-rich structural types represent particular and impoverished subsets of those found in the richer ones. The study was conducted at Fazenda Palmares (5°33′S, 42°37′W) Piauí State, Brazil. A 47% decrease in woody plant density between cerradão (forest) and the least-dense type of cerrado sensu stricto (scrub) was associated with a 40% decrease in species richness. The percentage of lower-layer species was reduced by 29% in the least dense type of cerrado sensu stricto compared to cerradão. The proportion of species that flower and fruit during the rainy season was also reduced by one third. Species were not distributed as impoverished subsets along the cerradão–cerrado sensu stricto gradient. It is argued that the reduction in woody plant density and richness is partly due to factors limiting the occurrence of species with particular life-history strategies. The species composition of structural types is affected by the ‘mass effect’ and also by surrounding biotas, which provide species that colonize particular types of cerrado vegetation. Both these processes reduce the likelihood that the species composition in the poorer structural types are simple subsets of those present in the richer types.


2017 ◽  
Vol 37 (1) ◽  
pp. 1
Author(s):  
Agus Slamet ◽  
Bayu Kanetro

Protein content of winged bean is almost the same as soybean, but the beany flavor is more poweful than soybean. Therefore the protein of winged bean was isolated prior to use as raw material of yogurt. This research was aimed to determine the potency of  hypocholestrolemic activity of yogurt protein isolate of winged  bean through in vivo bioassay by using Sprague Dawley male rats. The treatments of the research were yogurt feed treatment with concentration of yogurt 0 (standard feed without yogurt as a control), 2, and 4 g yogurt/day as low and high concentration treatment respectively for 4th weeks after hypercholesterol feed  treatment for 1 week. The blood lipid profile of rats, including triglyceride, cholesterol total, High Density Lipoprotein (HDL), Low  Density Lipoprotein (LDL) cholesterol were analysed on the 2nd  and 4th weeks for the yogurt feed treatment while for before  yogurt feed treatment, the evaluation were based on the  adaptation phase and the 1st week for hypercholesterol phase.  The result of this research showed that the blood triglyceride,  cholesterol total, LDL increased, and the blood HDL decreased in hypercholesterol phase before yogurt feed treatment. The potency of hypocholestrolemic of yogurt from protein isolate of winged  bean was shown by the decreasing of blood triglyceride,  cholesterol total, LDL and increasing the HDL cholesterol after the yogurt feed treatment with low and high concentration. That  indicated that yogurt that was made of protein isolate of winged  bean could reduced cholesterol. ABSTRAKBiji kecipir memiliki kadar protein yang hampir sama dengan  kedelai, namun bau langunya lebih tajam daripada kedelai,  sehingga perlu diisolasi proteinnya sebelum digunakan sebagai  bahan baku yogurt. Tujuan penelitian ini adalah menentukan  potensi hipokolesterolemik yogurt isolat proteun biji kecipir  melalui uji biologis in vivo menggunakan tikus jantan Sprague Dawley. Perlakuan penelitian ini adalah perlakuan pakan yogurt  dengan konsentrasi 0 (pakan standar tanpa penambahan yogurt sebagai kontrol), 2, dan 4 g yogurt/hari berturut-turut sebagai  perlakuan konsentrasi rendah dan tinggi selama 4 minggu  perlakuan pakan yogurt sesudah pemberian pakan hiperkolesterol selama 1 minggu. Profil lipida darah tikus meliputi kadar trigliserida, total kolesterol, kolesterol High Density  Lipoprotein (HDL), dan Low Density Lipoprotein (LDL) dianalisis  pada minggu ke 2 dan 4 minggu selama perlakuan pakan yogurt  dan sebelum perlakuan pakan yogurt yaitu pada fase pemeliharaan adaptasi dan 1 minggu pada fase pemeliharan  hiperkolesterol. Hasil penelitian ini menunjukkan bahwa  trigliserida, total kolesterol, dan kolesterol LDL meningkat dan kolesterol HDL menurun selama fase pemberian pakan  hiperkolesterol sebelum perlakuan pakan yogurt. Potensi  hipokolesterol yogurt isolat protein biji kecipir ditunjukkan dengan penurunan trigliserida, total kolesterol, dan kolesterol LDL, serta peningkatan kolesterol HDL sesudah perlakuan pakan yogurt dengan konsentrasi rendah maupun tinggi. Hal tersebut mengindikasikan bahwa yogurt isolat protein biji kecipir mampu menurunkan kolesterol.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1203
Author(s):  
Evaggelia Sinapidou ◽  
Chrysanthi Pankou ◽  
Fotakis Gekas ◽  
Iosif Sistanis ◽  
Constantinos Tzantarmas ◽  
...  

The study pertains to field experimentation testing seven maize (Zea mays L.) hybrids at four densities, across five locations under normal (NIR) and low-input (LIR) regimes. The main objective was to assess the prognostic value of plant yield efficiency by homeostasis (PYEH) for breeding purposes at ultra-low plant density to predict hybrid yield potential and stability. PYEH comprises plant yield efficiency (PYE) that reflects the ability of individual plants to exploit resources, and plant yield homeostasis (PYH) that indicates the crop’s ability to evade acquired plant-to-plant variability. The same hybrids were also evaluated for stability by commonly used parametric and non-parametric statistics based on data at low (LCD) and high crop densities (HCD). Hybrid stability focused on potential yield loss due to erratic optimum density (OD). Most methods produced conflicting results regarding hybrid ranking for yield and stability especially at LCD. In contrast, PYEH consistently highlighted high-yielding and stable hybrids, potentially able to reach the attainable crop yield (ACY) inter-seasonally irrespective of crop spacing. Low density is common practice under resource-deficit conditions, so crop adaptation to crop spacing is a viable option to overcome erratic OD that constitutes a root source of crop instability in rainfed maize. The results were further supportive of breeding at ultra-low density to facilitate the identification and selection of superior genotypes, since such conditions promote phenotypic expression and differentiation, and ensure repeatability across diverse environments.


Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 479 ◽  
Author(s):  
Hanif ◽  
Guo ◽  
Moniruzzaman ◽  
He ◽  
Yu ◽  
...  

Plant attributes have direct and indirect effects on soil microbes via plant inputs and plant-mediated soil changes. However, whether plant taxonomic and functional diversities can explain the soil microbial diversity of restored forest ecosystems remains elusive. Here, we tested the linkage between plant attributes and soil microbial communities in four restored forests (Acacia species, Eucalyptus species, mixed coniferous species, mixed native species). The trait-based approaches were applied for plant properties and high-throughput Illumina sequencing was applied for fungal and bacterial diversity. The total number of soil microbial operational taxonomic units (OTUs) varied among the four forests. The highest richness of fungal OTUs was found in the Acacia forest. However, bacterial OTUs were highest in the Eucalyptus forest. Species richness was positively and significantly related to fungal and bacterial richness. Plant taxonomic diversity (species richness and species diversity) explained more of the soil microbial diversity than the functional diversity and soil properties. Prediction of fungal richness was better than that of bacterial richness. In addition, root traits explained more variation than the leaf traits. Overall, plant taxonomic diversity played a more important role than plant functional diversity and soil properties in shaping the soil microbial diversity of the four forests.


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